Process of binding the active material of positive-pole lead electrodes.



" UNITED STATES PATENT oFFioE;

WILLIAM MORRISON, or. mas Momns, Iowa;

No Drawing.

- T all whom it may concern:

Be it known that I,,Wii.i.i.\1i Momusox, a citizen of the United States, residing at Des Moines, in the county of Polk and State of Iowa, I have invented certain new and useful Improvements in Processes of Binding the Active Material or Positive-Pole Lead Electrodes, .of which the following is a specification. v

This invention relates to the production of a'permanentand insoluble binder for the active material of the positive-pole electrodes of lead storage batteries. This binder fundamentally comprises an oxygen compound of niobium, a-metal which is incapable of directly replacing hydrogen in a sulfuric acid solution; insoluble by anodic oxidation, in a. sulfuric acid solution; incapable of cathodic reduction to metal, or of electrolytic separation as metal. in a sulfuric 'acid solution; and capable of forming complexanions-with electronegative elements.

which can constitute the acidic radical of compounds having lead as a base.

To illustrate the invention, there will first I be described an electrolytic process of producing a lead-peroxid electrode employing a compound of niobium as the binder. F or this purpose. a metallic support. for example a grid of antimonial lead. is pasted or filled with the usual mixture of ininium, litharge and a sulfuric acid solution. in which mixture lead sulfate forms as a provisional binder. (omplete formation, or pet-oxidation. of the. active material is then preferablyinitially etl'ected by placing the.

i .-pa st ed grids. alternately with unfilled grids servng as dummy electrodes of the opposite polarity. in a sulfuric acid solution having a specific gravity-of 1.200 to 1,250 and iassin" an electric current throu 'h the so b b -lution, alternately in opposite directions.

lllttil the-'paste. has been sufficiently -ex'- panded. care being taken notto force the discharge beyond the normal intended ca pacity. of the electrodes. dummy electrodes are then removed-from -the sulfuric acid 'sohltlon and-placed in a The formed and cell containing.water,and electric current is passed from the filled electrodes :to the dummies until the-tree acid in the active material has been ren'toved. The electrodes and dummies are then removed, rinsed in water, and placed in a strong aqueous solution of an a1kali-metal niobate, for example potassium hexaniobate. An electric Specification of Letters Patent.

Application filed February 24, 1912. serious-679.703;

.scribed are ng'it suited; vfo

electrode. A v

'lhe. niolnum-onvgenanion appears to .play the same rfile -ln the .bmder compound "PROCESS OF BINDING THE ACTIVE MATERIAL 0F I OSI'EIVE-POLIE-LIEJAD'151315(STRODES.

' -Pa'tente d Apt. 2; 1912.

current is then passed fromtlie filled electrodes through the solutionto the dummies, and iscontinuedfor several hours,.t h ereby causing niobium ions,. presumably complex niobium-oxygen ions, to penetrate the active .material to any desired degree and to combine chemically iritlrtlie lead-oxygen compounds thereof, and particularly \vitlrthe lead-sulfate which'serves as the provisional binder in the electrode. The electrodes and dummies are then re1noved,'rinset l in water,

placed in a sulfuric, acid solution having a specific gravity of about l.300, and anelectric current is passed from the electrodes to the dummies until allof the-soluble constituents of theactive iii aterial have. been" removed or renderedinsoluble; 'lhei'electrodes are, thenfdischarged to the extent oi their normal.{capacitg an ,11ieteam re charged. preferably. to shut less than their full capacity in anothersuljuridacid solutionof 1.280 specific gravit v. the effect-- of such incomplete recharging beingto leave in the plate a certa in proportion of lead sulfate to combine wrthth n ob um ionson a repetition of t repetition be desired, fortlie purpose of impregnatingthe active material rwith adasn'loes the:sulfurroxygeu anion in the ordinal-plead-electrodes in which lead sulfate constitutes. the binder. 'l-helead-'niohiutm o-vve'onct uupotuu Iv. hmvcv-cr. as compared with the lead sull'ate heretoforecommonly used as a binder very permanent and insoluble. .The niobimn compound has a. considerable capacity for binding Slllfl.| .tl0 acid.

he:- treatment, should such at once treated in the niobium solution to" impregnate the active material with the binder, formation being subsequently efi'ected. Such subsequent formation, however, consumes a much larger amount of current than does initial formation.

Tihile the described electrolytic process of impregnation is an efficient and operative one, it is sometimes preferable, particularly with thick plates, in order to more uniformly distribute the binder throughout the active mass, to incorporate a portion of the binder with the active material by another method, which will now be described. This method consists in forming an aqueous solution of a suitable lead salt, as lead nitrate or acetate, adding potassium hexaniobate, or hexaniobate plus hexatantalate, until all the lead is precipitated as a niobium-oxygen compound, or mixture of niobium-oxygen and tantalumoxygen compounds, separating the precipitate and washing it with dilute sulfuric acid, then boiling it in strong sulfuric acid, and washing it with water, 7 The precipitate may be heated, in order to give it a denser body. The desired proportion of this product, say from six to ten per cent. or more, is very thoroughly mixed with theminium-litharge paste, as by grinding the materials together. The positive-pole electrode treated by this preliminary method should receive a prolonged and strong chargingtreatment in sulfuric acid, with dummy negatives, before assembling in the battery, in order to remove or to render insoluble any remaining soluble components of the plate. The electrode is then finished by the electrolytic method heretofore described, that is, by connecting it as the anode in a solution of a niobate, to impregnate the active material, and especially the outer portions thereof,- with a binder-compound containing niobium.

It is to be understood that the several foregoing examples are illustrative in character, and that. the invention is not limited to the details of manipulation or to the strength or proportions of reagents recited; and it is also to be understood that the positive-pole electrodes may be prepared by methods other than those herein specifically described without departure from my invention. The active material of Ilant electrodes, formed out of solid lead, ma y also be bound by employing them as anodes in a solution of a niobate.

- I claim:

1. In a process of binding the active material of positive-pole lead electrodes, the step which consists in electrolytically impregnating the active material with a compound contaming niobium in its acidic radical.

2. In aprocess of binding the active material of positive-pole lead electrodes, the step which consistsin passing an electric current from 'theelectrode through a solution of a niobate, thereby impregnating the active material with a niobium compound. 3. The process of binding the'active material of positive-pole lead electrodes, which consists in passing an electric current from the electrode through a solution of a niobate, thereby impregnating the active material with, a niobium compound, and thereafter reacting on said compound with sulfuric acid.

4. The process of binding the active material of. positive-pole lead electrodes, which consists in passing an electric current from the electrode through asolution of a niobate, thereby impregnating the active material with a niobium compound, and thereafter electrochemically reacting on said compound with sulfuric acid.

5. The process of binding the active materialof -positive-pole lead electrodes, which consists in passing an electric current from the electrode through a solution of a niobate, thereby impregnating the active material with a'niobium compound, and thereafter electrochemically reacting on said compound with sulfuric acid.

6. The process of binding the active material of positive-pole lead electrodes, which consists in reacting on a solution of a lead salt with a compound or compounds of a metal or metals incapable of directly replacing hydrogen in a sulfuric acid solution; insoluble by anodic oxidation 'in a sulfuric acid solution incapable of cathodic reduc tion to metal, or of electrolytic separation as metal, in a sulfuric acid solution; and capable of forming complex anions with electro negative elements, which can constitute the acidic radical of compounds having lead as a base, mixing the reactionroduct with the active material, applying t e mixture to a support to constitute an electrode, passing an electric current, from -the electrode through a solution of a niobate, thereby impregnating the active material with a compound of'niobium, and electrochemically reacting on said compound with sulfuric acid.

7. The process of binding the active material'of posit-ive.-.p ole lead electrodes, which consists in reacting on a solution of a lead salt with a compound of niobium, mixing the reaction-piipduct with the active material, applying t e mixture to a sup ort to constitute an electrode, passing an e ectric current from the electrode through a solution of a niobate, thereby impregnating the active material with a compound of niobium, and electrochemically reacting on said compound with sulfuric acld.

8. The process of binding the active material of positive-pole lead electrodes, which consists in reacting on a solution of a lead salt with compounds of niobium and tantalum, mixing the reaction-product with the active material, applying the mixture to a support to constitute an electrode, passing an electric current from the electrode through a solution of a niobate, thereby impregnating the active material with a compound of n1obium,-and electrochemically. re-

WILLIAM MORRISON.

Witnesses:

EUGENE A. BYRNES, JAB. H Bmcxwoon.

Copies of this patent may be obtained for five cents each, by addressing the Gommissioner of Patents,

. Washington, D. G. 

